Consumers may wonder how it is that they get ads, emails and other information from companies with whom they have had no interaction on or off-line. Maybe they’re particularly confused if they’ve set their privacy settings to block cookies and other tracking devices.

The reality is that data brokers gather, compile and then sell lists of personal information to companies. So what can consumers do if they want to try and protect their information from being compiled and sold by data brokers? The answer is “it’s not easy” especially given the numbers of data brokers and the range of information they collect.

Julia Angwin has written a newly published book, Dragnet Nation, that focuses, in part, on her efforts to identify data brokers and then get the information that brokers have about her. I plan on reading her book as I heard her discuss it recently and have just read her January 30th article, “Privacy Tools: Opting Out from Data Brokers” posted on ProPublica (www.propublica.org).

Her ProPublica article summarizes the steps required by some of the data brokers in order for her to opt-out of information collection. As Ms. Angwin writes, there’s no law requiring data brokers to offer consumers that option. She very helpfully attaches two spreadsheets to her article with the names of companies tracking information along with links to their privacy pages and, for those data brokers offering an opt-out, the instructions for doing so. As she writes, many of the data brokers require consumers who want to opt-out to provide personal information and identification (e.g., driver’s license).

Ms. Angwin’s spreadsheets of 212 data brokers provides consumers with a very useful resource. She is also very candid in describing the difficulties in finding her own information and what she calls “some minor successes” in finding data brokers who had her information and opting-out.